1. Field of the Invention
The present invention relates generally to an arrangement by which portable, free-standing ladders, tripods or other type supports that may be quickly positioned upon an irregular surface to provide an upright position having inherent stability.
2. Description of Prior Art
Devices that extend an upright side rail of a ladder or a tripod to permit said device to stand on uneven ground in a safe, upright position with a maximum of stability have at various times been developed. However, such devices are usually cumbersome, they have insufficient scope of adjustment, and most importantly, they are only slowly activated to obtain the proper results so that they find little use on fire fighting equipment and the like where rapidity of adjustment is extremely important.
Known devices are exemplified by U.S. Pat. No. 3,791,487 where each side beam of a ladder is provided with an extensible leg that may be moved lengthwise to provide the proper overall length. A manually operated knurled nut is turned to activate the locking mechanism by which each leg is supported in a predetermined position.
In U.S. Pat. No. 3,805,917 the legs of a ladder are mounted on the ends of a torsion bar having shoes that extend therefrom in opposite directions. While this adjusting means is readily actuated, it fails to provide maximum adjustment of one leg independent of the other.
Various other leg extension means have been developed, but they too invariably are complex, expensive and only laboriously activated. Most important, however, remains the fact that they are not rapidly adjusted to provide the proper length required for maximum stability.